The invention relates to a cutter block for a motor driven hand planer.
From the European patent application No. 0048303, there is known a cutter block in which a one-piece roller body is provided with adjusting and tightening means for conventional planing knives. Symmetric to the rotational axis of the roller body, two groups of gripping surfaces for a respective knife, a clamping holder and a pressing strip are fixed to the roller body. The basic body is provided with five tapped holes perpendicular to these gripping surfaces and extending through the longitudinal axis of the basic body. Two holding screws are screwed into these tapped holes from each side for fastening a respective one of the clamping holders and a knife held by the respective clamping holder. Through the provision of a longitudinal groove in the knife and a corresponding corrugation on the clamping holder, a form lock is obtained between the clamping holder and the knife. For adjusting the knife, oblong holes are provided in the clamping holder through which five screws are guided. The adjusted position of the knife is maintained by two holding screws of the clamping holder. Thereafter, the knife and the clamping holder are fixedly pressed to the basic body by the pressing strip by means of three tightening screws provided in the remaining tapped holes.
Although such a cutter block permits the adjustment of the respective knife, it exhibits nevertheless the inherent disadvantage that the construction and the design of the entire cutter block as well as the provision to adjust the knife is rather cumbersome.
A further cutter block is disclosed in the European patent application No. 008798. The cutter block is a one-piece roller body which is provided with longitudinal bore holes in the vicinity of the roller shell and extending into the roller shell. Inserted in these longitudinal bore holes is a special knife bolt. The knife bolt is produced by milling two cylindrically opposing longitudinal grooves in a rod of circular cross section. Consequently, four cutting edges are obtained which can successively be used. The knife bolts within the longitudinal bore holes are permanently kept within the same position by tightening screws which can be tightened through the roller body against the knife bolts. This cutter block has also several disadvantages. The machining of the roller basic body is rather cumbersome and expensive and moreover, the cutting edges of the knife bolts cannot be adjusted into different positions in the roller shell of the roller body. Finally, conventional planing knives cannot be used.